Addressing the substantial disparity in health between low and high socioeconomic status (SES) groups requires a detailed understanding of the complex interaction between dimensions of SES (such as, education, income and wealth) and those of health (including disability and mortality). Progress has been made in recent years in characterizing the relationships between the various dimensions of SES and health over the lifecycle and in understanding the relative importance and directions of causal pathways. Yet, despite these advances in knowledge little is known about many of the mechanisms that produce the observed causal relations. Progress is hampered by the lack of a comprehensive theoretical framework to interpret empirical facts. It is no surprise then that recent reviews of the literature point to the absence of such a unifying theory and emphasize the importance of developing one. We have recently made substantial efforts toward the development of a unified theoretical framework for analyzing health and socioeconomic status trajectories over the lifecycle. Our theoretical framework aims to understand the SES-health gradient as the outcome of rational (but constrained) individual behavior. The structural model contains many potential mechanisms that could explain disparities in health by SES. Of particular importance appear to be lifestyle factors (preventive care, healthy and unhealthy consumption), work conditions (job-related health stress)1, curative care and the constraining effect of health on work. Empirical testing is needed to distinguish important from less important mechanisms. The objectives of this research are (i) to derive new, testable predictions from this framework; (ii) to test these predictions using existing panel data from the US and European countries. The aim of these tests is not only to establish plausible causality but to evaluate the underlying mechanisms that produce the causal relationships; and (iii) to couple the estimated models with international variation in institutions to inform policy and decision makers about the relative effectiveness of alternative public policies to reduce disparities in health. The specific aims of the proposed research are to: 1) improve our understanding of mechanisms responsible for socioeconomic disparities in health using a structural model of lifestyle and work; 2) use the structural model to empirically assess the importance of lifestyle and job-related health stress with the richest panel data available to date; 3) evaluate the contribution of health-induced labor-force withdrawal to health disparities; and 4) assess the effects of institutions and public policies on creating/moderating health disparities. 1 The concept of job-related health stress can be interpreted broadly and can range from physical working conditions (e.g., hard labor) to psychosocial aspects of work (e.g., low status, limited control, repetitive work, etc). The notion here is that it can include any aspect of work that is detrimental to health and as such is associated with a wage premium (relative to an imaginary situation where there would not be a detrimental affect on health). PUBLIC HEALTH RELEVANCE: Without a detailed understanding of the causes of the substantial disparities in health between low and high socioeconomic status groups, policies aimed at reducing such disparities are likely to be ineffective. We have recently made substantial efforts toward the development of a structural model that allows for many potential mechanisms that could explain disparities in health by SES over the lifecycle. The objectives of this research are (i) to derive new, testable predictions from this framework, (ii) to test these predictions using existing panel data from the US and European countries, and (iii) to use the estimated models and international variation to inform policy and decision makers about the relative effectiveness of alternative public policies to reduce disparities in health.